Engineer or Mesmer?
Mesmer gets dull once you realize how bland their skills are when you look past the illusions. It’s definitely the more viable class and I recommend having one….
But overall, I’d say Engineer is more entertaining. Learning to properly alternate between kits and their main-hand weapon gives them quite a bit of depth and allows for more interesting play than the Mesmer is capable of.
In groups, Mesmers are more appreciated thanks to having a host of mobility and support skills such as Time Warp, Portal, Feedback, and Temporal Curtain. When played properly, Mesmers can set up amazing spikes and impressive techniques that can change the way your group goes about something. Engineers tend to be less appreciated thanks to having generally weaker support and misperceived damage capabilities. On the other hand, Engineers can pump out cripple, immobilize, have access to pretty much every type of crowd control, incredible mobility, and do very heavy AoE damage with bombs and grenades. When played properly, Engineers have the widest variety of skills available to them compared to any class in addition to being able to pour out steady damage on par with a Thief or a Warrior (excluding Hundred Blades) almost entirely at long range.